abinit学习日记十二——tbase4_2.abi

接着对k点进行收敛性测试。

# Crystalline aluminum : optimization of the lattice parameter
#
# Convergence with respect to k points.

ndtset 4
getwfk -1
# -1 读取上一个操作获得的波函数

#Definition of the unit cell
acell 3*7.60           # This is equivalent to   7.60 7.60 7.60
rprim  0.0  0.5  0.5   # FCC primitive vectors (to be scaled by acell)
       0.5  0.0  0.5
       0.5  0.5  0.0

#Definition of the atom types
ntypat 1          # There is only one type of atom
znucl 13          # The keyword "znucl" refers to the atomic number of the
                  # possible type(s) of atom. The pseudopotential(s)
                  # mentioned in the "files" file must correspond
                  # to the type(s) of atom. Here, the only type is Aluminum
pp_dirpath "$ABI_PSPDIR"       # This is the path to the directory were
                               # pseudopotentials for tests are stored
pseudos "Psdj_nc_sr_04_pw_std_psp8/Al.psp8"
                               # Name and location of the pseudopotential

#Definition of the atoms
natom 1           # There is only one atom per cell
typat 1           # This atom is of type 1, that is, Aluminum
xred              # This keyword indicate that the location of the atoms
                  # will follow, one triplet of number for each atom
0.0  0.0  0.0     # Triplet giving the REDUCED coordinate of atom 1.

#Definition of the planewave basis set
ecut  6.0         # Maximal kinetic energy cut-off, in Hartree

#Definition of the k-point grids
nshiftk 4
shiftk  0.5 0.5 0.5  # These shifts will be the same for all grids
        0.5 0.0 0.0
        0.0 0.5 0.0
        0.0 0.0 0.5

ngkpt1  2 2 2
ngkpt2  4 4 4
ngkpt3  6 6 6
ngkpt4  8 8 8

#Definition of the SCF procedure
nstep 10          # Maximal number of SCF cycles
tolvrs 1.0d-14    # Will stop when, twice in a row, the difference
                  # between two consecutive evaluations of total energy
                  # differ by less than toldfe (in Hartree)
                  # This value is REASONABLE for most realistic studies of materials

#Definition of occupation numbers
occopt 4
tsmear 0.05

#Optimization of the lattice parameters
optcell 1
geoopt  "bfgs"
ntime  10
dilatmx 1.05
ecutsm  0.5

输出结果

nkpt1  2
nkpt2 10
nkpt3 28
nkpt4 60
# 有效的k点数量依然是这几个

tsmear 和 k 点互相影响，必须先把 k 点收敛，再比较不同 tsmear 的收敛值。

在后续的操作中，我们将仅仅使用 k = 2，10，28的网格。